NT
Unicolored Thrush Turdus haplochrous



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
SACC. 2005 and updates. A classification of the bird species of South America. Available at: https://www.museum.lsu.edu/~Remsen/SACCBaseline.htm.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2023 Near Threatened C2a(ii)
2016 Near Threatened C2a(i)
2012 Near Threatened C2a(i)
2011 Near Threatened C2a(i)
2008 Near Threatened C2a(i)
2004 Near Threatened
2000 Lower Risk/Near Threatened
1994 Lower Risk/Near Threatened
1988 Near Threatened
Species attributes

Migratory status not a migrant Forest dependency medium
Land-mass type continent
Average mass -
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 122,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 2500-9999 mature individuals poor suspected 2022
Population trend decreasing poor suspected 2016-2027
Rate of change over the past 10 years/3 generations (longer of the two periods) 1-9% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 10-19% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 10-19% - - -
Generation length 3.75 years - - -
Number of subpopulations 1 - - -
Percentage of mature individuals in largest subpopulation 100% - - -

Population justification: The global population size has not been quantified. Despite some survey effort in potentially suitable habitat the species is only occasionally recorded, and is assumed to be genuinely rare (Collar and Sharpe 2020, eBird 2022). The population is therefore here tentatively placed in the band 2,500-9,999 mature individuals.
Its inconspicuous and silent habits during the dry season may however lead to it being under-recorded (Collar and Sharpe 2020); an accurate quantification of the population size is urgently required.

Trend justification: There are no data on the population trend, but declines are suspected on the basis of the species' forest dependence and ongoing deforestation in the region.
Over the past three generations (11.3 years), 7% of tree cover has been lost within the range; since 2016 this has been increasing to a rate equivalent to 12% (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). Under the assumption that population declines are roughly equivalent to the rate of tree cover loss, the species is suspected to have declined by 1-9% over the past three generations. With increasing deforestation, population declines are likewise suspected to accelerate, to a rate of 10-19% over three generations into the future.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Bolivia extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Swamp major resident
Altitude 0 - 350 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Small-holder grazing, ranching or farming Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion

Recommended citation
BirdLife International (2024) Species factsheet: Unicolored Thrush Turdus haplochrous. Downloaded from https://datazone.birdlife.org/species/factsheet/unicolored-thrush-turdus-haplochrous on 22/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/12/2024.